The present invention relates to a device and a method to measure the infrared radiation flux in connection with the temperature difference on human body surface. More particularly, the present invention relates to a device and a method used to measure, from outside the covering on the human body, the IR radiation flux in connection with the skin temperature difference between the spot on the human body surface corresponding to a person's internal organ and its adjacent spots on the body surface.
Humans are animals with a constant body temperature. Human body temperature is maintained constant through a dynamic balance comprising processes of controlling heat generation and dissipation under the action of behaviour and self adjustment. From the physiological view, when a person is quiet, about 50% of his body heat is generated by his internal organs. At ambient temperatures of 16.degree. to 25.degree. C., more than 50% of the total dissipated body heat is dissipated through body skin radiation. From the pathological point of view, when a person is sick or the physiological state of his organs is changing, the metabolism of his internal organs and tissues and the amount of heat generated by them will also change, thus disrupting the thermal balance of part or the whole of the body. Clinically, this is reflected in the rise or fall of the temperature of the organ. Since the amount of heat generated by the various internal organs and the metabolization rate of the human body are different, the heat contribution or the micro heat increment of the various heat-generating organs is different in the corresponding shallow skin of the body. If such temperature variation in the various parts on the body surface is measured, important physiological data will therefore be provided for assessing the level of the metabolic function of a person's internal organs and his tissue energy.
A common method to measure the temperature of a human body is to use a rod-shaped mercury thermometer. Recent years have seen thermometers made of semi-conductor materials or metal. Although these thermometers incorporate significant improvements in both operation method and accuracy, they are still not accurate enough to measure the heat contribution or the minute temperature difference (normally 0.01.degree. to 0.05.degree. C.) formed in the corresponding spots in the skin due to energy metabolism of the various internal organs and tissues.
People tried to resolve the minute temperature difference between the various parts in the body skin by using an IR thermal imager with a temperature resolution of 0.01.degree. C. Unfortunately IR thermal imagers with such a high resolution are still unable to find the truth of the energy metabolism of a person's internal organs and tissues. This is because when an IR thermal imager is used to measure the temperature characteristics in the body skin (at room temperatures of 16.degree. to 25.degree. C.), the tested person has to bare part of his body for measurement and allow that part of his body to stay put for quite a long time. During the stay-put period, the body skin temperature of the tested person varies correspondingly with the varying ambient temperature as he is under the influence of the ambient temperature, humidity and air flow and also under the action of self adjustment as shown by the group of curves on the left side of FIG. 1A. This upsets to varying extents the micro heat increment (0.01.degree. to 0.05.degree. C.) that reflects the level of energy metabolism of the internal organs and tissues. Contrary to this, if the person does not have to bare part of his body for measurement, the adjustment of the thickness of the coverage on the body surface can keep the body surface temperature unchanged with the variation of the ambient temperature, as shown by the group of curves on the right side of FIG. 1A. Furthermore, when a person bares his body for measurement, he will be forced to rely entirely on self adjustment to be adaptive to the changes in ambient temperature and other factors. This physiological inadaptivity will also disrupt the temperature characteristics in the body skin that reflects the level of energy metabolism of the internal organs and tissues. Since nakedness, especially the nudity of the trunk or the chest, is an unnatural human behaviour that runs counter to moral principles, the person in question will feel nervous and out of the place, such psychological inquiety will also disrupt the temperature characteristics in the body skin. Besides, from the physiological point of view, heat generation or metabolism of the various internal organs and tissues will be normal when a person feels warm and comfortable. FIG. 1B shows the results of tests on the sensitivity of a completely nude person to ambient temperature. Only when ambient temperature rises to 31.degree.-34.degree. C. will the human body feel warm and comfortable. However, in such a case, heat dissipates from the human body through evaporation (perspiration), which disrupts the body skin temperature even more severely. In order to avoid heat dissipation by evaporation, maintain relatively high body skin temperature and make a person's body feel warm and comfortable, the following conditions, must be met:
(1) Ambient temperature is below 25.degree. C.;
(2) The part of body for measurement must have a covering of a certain thickness or be covered with suitable clothes so that the temperature difference between the body surface and the covering surface is about 10.degree. C.
When the part of body for measurement, especially the chest or the trunk is covered with clothes (coverings) of suitable thickness instead of being nude, the effects of the variation of ambient temperature, humidity and air flow will be reduced greatly and the physiological and psychological disruption caused by a behaviour violating human moral principles will also be eliminated.
In such conditions (relatively no-interference state), the heat contribution or the micro heat increment in the body skin that reflects the level of energy metabolism of internal organs and tissues are free from the various interferences.
In order to measure the micro heat increment superimposed on the body skin, people tried in a vain attempt to detect the minute temperature difference between various parts of body skin by applying an IR thermometer or thermal imager with an even higher temperature resolution to the coverings on the human body. Such a failure results from the fact that when a thermal imager is used to measure the temperature characteristics in the coverings on the body, the inhomogeneity of the gaps between the body skin and the coverings causes the thermal resistance of the coverings to be inconstant. If the tested person wears tight-fitting clothes to bring his body skin into uniform contact with the coverings, thus enabling the thermal resistance of the coverings to remain constant, the person will feel uncomfortable and have a psychology that affects the collection of the temperature signals. Therefore, presently available thermal imagers and measuring methods cannot be used to measure the micro heat increment superimposed on the body skin and reflecting the energy metabolism of internal organs and tissues.
One of the objects of this invention is to provide a device and method to measure the variation of the IR radiation flux density generated in the human body skin owing to various micro temperature differences (0.01.degree.-0.05.degree. C.) corresponding to an individual internal organ.
Another object of the invention is to provide a device and method to measure from the outside of the coverings on the human body the micro heat increment or micro temperature difference on the surface of the corresponding body skin during the process of energy metabolism of a person's internal organs and tissues when his body feels warm and comfortable without dissipating heat through evaporation.